1. Field of the Invention
An improved cutting edge on an end mill, method of production, and method of use are provided. In particular, the subject invention discloses an improved end mill having a highly or mirror polished chatter-dampening cutting edge land and a smoothed cutting edge to shank neck transition region and a procedure for producing same, wherein the improved cutting edge dampens vibrations during part machining and the smoothed transition region minimizes sharp corners on the machined part that roughen the part""s finished surface.
2. Description of the Background Art
Rotational end mills have been utilized for various cutting duties over many years. Numerous sharpening methods have been developed in the past. When a traditionally sharpened end mill, frequently composed of carbide and carbide alloys, rotationally encounters a substance like aluminum or the like, the mill begins to xe2x80x9cchatter,xe2x80x9d whereby the rotating end mill""s frequency of vibration self-excites and causes a poor finish on the machined part. The self-exciting chatter is usually accompanied by a loud noise while machining. The self-exciting chatter has been an inherent characteristic of long diameter to length cutting tools. In addition to the poor finish associated with the traditional chatter-producing end mill is a limitation with thin-walled aluminum parts. The end mill chatter may stress the thin-walled aluminum parts beyond structural limits and produce unacceptable parts. Further, chattering can dull the cutting edge of an end mill and limit its useful life, thereby increasing costs for the milling operation and generating less precise machined parts than may be desired or required for a particular final function.
Specifically, U.S. Pat. No. 5,467,670 discloses a chemical vapor deposition (CVD) process for attempting to keep the edges of rotary cutting tools sharp. The high temperatures in this process cause a chemical reaction to occur on the surface of the cutting tool. Generally, the process involves final grinding on all surfaces except the flank faces. All of the surfaces of the tool are then wear coated with a CVD process at a high enough temperature to embrittle the sharp, rough ground cutting edges. The flank faces are then ground to specification sharpness, thereby removing the embrittled layer on the flank faces while leaving the rake faces CVD coated. If desired, a final PVD wear layer coating may then be applied.
Disclosed in U.S. Pat. No. 4,945,640 is a wear resistant coating for sharp-edged tools and the like. Usually, a base layer of noble metal is formed on the surface followed by an intermediate layer of tungsten and a final coating of a mixture of tungsten and tungsten carbide.
U.S. Pat. Nos. 3,874,900 and 3,988,955 both relate methods for coating wear surfaces with vapor deposits.
U.S. Pat. No. 4,470,895 presents an ion plating method for depositing a coating. The method stop the application of the coating immediately next to where the cutting edge begins so as to leave the cutting edge not covered.
In U.S. Pat. No. 5,477,616 the body of a knife blades is coated with a hard material in such a manner as to permit the entire cutting edge to be formed from the harder material.
Six patent from Japan (Nos. 51-42,029; 51-42030; 55-120937; 55-131173; 55-144937; and 56-3152) illustrate the use of various compositions of hardening material on the surfaces of cutting implements.
U.S. Pat. No. 6,105,467, by the subject inventor, discloses a method of increasing the length of time a tool maintains sharp cutting edges. The method utilizes the steps of manufacturing the tool with the cutting edges ground sharp and then partially dulling, to a lighter or heavier extent, those previously ground sharp cutting edges. Often the partial dulling is accomplished by means of applying a brush wheel to the selected cutting edges.
The foregoing patents reflect the state of the art of which the applicant is aware and are tendered with the view toward discharging applicant""s acknowledged duty of candor in disclosing information which may be pertinent in the examination of this application. It is respectfully submitted, however, that none of these patents teach or render obvious, singly or when considered in combination, applicant""s claimed invention.
An object of the present invention is to provide an improved end mill that reduces chatter during usage, thereby producing better finishes on milled parts.
Another object of the present invention is to furnish an improved end mill having a feathered blend that smoothes a cutting diameter to a neck/shank diameter that helps to eliminate steps and mismatching of side walls when multiple axial depths are required to finish a side wall in a milled part.
A further object of the present invention is to supply an improved end mill that has a mirror polished cutting land which minimizes chattering during milling of a part.
Still another object of the present invention is to disclose a method of producing an improved end mill in which the produced end mill has a mirror polished cutting land and a feather blend that smoothes a cutting diameter to a neck/shank diameter.
Disclosed is an improved end mill having a neck/shank with a neck/shank diameter, a cutting end with a cutting end diameter, a flute formed within the cutting end, and a cutting edge formed along an outer border of the flute, with the improvement comprising a highly or mirror polished cutting edge land extending from the cutting edge, a primary angle land continuing from the mirror polished cutting edge land and extending into the flute, a secondary angle land adjoining the primary angle land and terminating within the flute, and a smoothed transition region between the cutting end diameter and the neck diameter.
Additionally a method for producing the improved end mill is disclosed. The method to make the improved end mill includes the steps of producing a ground cylindrical member with a smoothed surface, wherein the ground cylindrical member includes a chamfered shank and a potential cutting end of appropriate diameter and length, polishing the potential cutting end of the ground cylindrical member to a mirror finish with a polishing wheel and polishing compound, grinding and polishing at least one flute (usually two) into the potential cutting end of the mirror finished cutting end, wherein a cutting edge is produced and a mirror polished cutting edge land that extends from said cutting edge to said flute, grinding primary and secondary angle lands within the flute, wherein the primary angle land continues from the mirror polished cutting edge land and extends into the flute and the secondary angle land is adjoining the primary angle land and terminating within the flute, and producing a smoothed transition region between the cutting end diameter and the neck diameter by means of a partially angled grinding wheel.
Other objects, advantages, and novel features of the present invention will become apparent from the detailed description that follows, when considered in conjunction with the associated drawings.